1. Field of the Invention
The present invention relates to a catalyst for polymerization of olefins or styrenes, and to a method for producing polymers. Precisely, the invention relates to a catalyst for polymerization of olefins or styrenes, which has the advantage of efficiently and inexpensively producing olefinic polymers or styrenic polymers, and also to a method for producing polymers in which is used the catalyst.
2. Description of the Background
Recently, catalysts for polymer production comprising, as the catalytic component, a transition metal compound having a .pi.-ligand, which are referred to as metallocene catalysts, have been developed and used in producing olefinic polymers and styrenic polymers.
However, the catalysts require a large amount of a catalyst promoter such as aluminoxanes in order that they could display high polymerization activity. Therefore, the catalysts are problematic in that their costs are high and that a catalyst residue derived from the catalyst promoter used remains in the polymers produced to cause coloration of the polymers.
In order to reduce the amount of the catalyst promoter to be used, techniques of using clay, clay minerals and the like in place of aluminoxanes have been proposed (see Japanese Patent Laid-Open Nos. 301917/1993 and 136047/1994). At present, however, the techniques could not still give high-activity catalysts capable of overcoming the problems noted above.